In optical communication systems, messages are transmitted typically through optical fibers by carrier waves of optical frequencies that are generated by sources, such as lasers or light emitting diodes. There is much current interest in such optical communication systems because they offer several advantages over other communication systems, such as having a greatly increased number of channels of communication and the ability to use other materials besides expensive copper cables for transmitting messages.
As the development of optical circuits proceeded, it became necessary to have optical waveguide devices which could couple, divide, switch and modulate the optical waves from one optical fiber to another, or from one waveguide device to another. For example devices see U.S. Pat. Nos. 3,689,264, 4,609,252 and 4,637,681.
Connecting optical devices to one another has traditionally been a problem. One method is to fuse or melt fibers or other configurations, for example, together so that light from one fiber or configuration can pass to the connected fibers or configurations. However, in such a fusion process it is difficult to control the extent of fusion and the exact geometry and reproducibility of the final structure.